Apparatus for the application of liquid substances



Jan. 16, 1968 G. DECKERT 3,

APPARATUS FOR THE APPLICATION OF LIQUID SUBSTANCES Filed Aug. 24, 1965 65/6 .A/n/Z 1) Z 5 anew T INVENTOR.

To 6' Jesiem 2 Sheets-Sheet 1 Jan. 16, 1968' G. DECKERT 3,3

APPARATUS FOR THE APPLICATION OF LIQUID SUBSTANCES Filed Aug. 24, 1965 2 Sheets-Sheet 2 FIG 5,18 11 19 i 1 \4 9 1 3 i1 x a FIG 3 FIG .4

LAMINATED LEAF SPRING mwm 1) 5c f g VINVENTOR.

United States Patent 3,363,605 APPARATUS FOR THE APPLICATION OF LIQUID SUBSTANCES Gerhard Deckert, Murnau, Post Schlossberg, Germany, assignor to Planatolwerk W. Hesselmann Chemische und Maschinenfabrik fur Klebetechnik Filed Aug. 24, 1965, Ser. No. 482,251 Claims priority, application Germany, Aug. 25, 1964, P 34,952 4 Claims. (Cl. 118-415) ABSTRACT OF THE DISCLOSURE Apparatus for the application of viscous liquids, (e.g. adhesives) to webs of sheet material passed between a container and a firm support pad; the container has a wall confronting the pad provided internally with a recess and, in a thin-walled portion thereof, a dispensing orifice selectively blocked and unblocked by one end of a leaf spring held against the thin Wall portion by a guide pin mounted in the recess. The major part of the length of the leaf spring is bent away from the Wall of the recess and is afiixed within the container to the movable rod of an electromagnet which extends through an opening in the container and is sealed with respect to the latter by an annular flexible diaphragm.

The invention relates to apparatus for the application of liquid substances, such as adhesives, and consists of a stationary, closed dispensing tank the walls of which are provided with at least one dispensing port capable of being closed, the object to be coated being moved past the perforated wall outside the dispensing port. A number of variations of apparatus of this kind are known.

In practice it has been found that particular advantages may be afiorded by one apparatus in which the strip of material to be coated, such as a strip of paper, is moved across a felt pad, and in which the dispensing tank is located on the side of the strip remote from the felt pad. The liquid is transferred from a reservoir through flexible tubes to the dispensing tank which has a comparatively small hollow space from which the liquid is dispensed through the wall of the tank.

In coating or application apparatus of this construction, the satisfactory opening and closing of the dispensing port under all operating conditions presents a problem. It would seem to be easy to solve this problem, and numerous proposals have been made of means and ways of closing such dispensing ports from the inside or outside. The best results have been obtained hithereto by providing a closure on the outside in the form of a foil which is stretched around the wall of the dispensing tank, and which carries out movement relative to the dispensing tank. It is also known to provide in the interior of the dispensing tank stamp-or pestle-shaped obturating tools which are moved by driving rods, magnets or the like, and, being provided in the form of a plunger or slide, are effective to seal the dispensing port.

When the known apparatus is used in practice, however, it appears, that the problem which at first blush seemed to be simple, is not so simple as had been thought, inasmuch as during the closing operation conventional obturating members cause considerable difficulties. Thus, for example, the known internal obturating members may move a substantial distance in the direction of the dispensing port during the closing operation, so that the liquid, disposed between the dispensing port and the obturating member in its inner end position, is forced out of the dispensing tank under a certain increase of pressure. Obturating heretofore provided in the form of slides have a similar effect, although in this case the amount of ejected liquid is not so substantial.

In any case, however, the additional quantity of efiiuent liquid results in a greater thickness of the coating than is desirable. In particularly drastic cases, the coating of liquid is smeared when the dispensing tank is closed and has thus an unattractive appearance.

On the other hand, when the dispensing tank is opened, that portion of the liquid which is disposed in the vicinity of the obturating member is first drawn back into the dispensing tank with the result that the liquid fails to be applied instantaneously as the tank is opened, since the inertia inherent in the liquid, and particularly with viscous adhesives, has first to be overcome.

These difiiculties are unavoidable in apparatus of know construction, so that such apparatus is unsuitable for carrying out a continuous method of application as required, for example, in the paper-working industry. It is particularly in the manufacture of paper bags, and in machines used in producing sets-of-forms, that it is desirable and frequently necessary for the coating of adhesive to be applied intermittently as well as continuously. It has also been found that in fact a quicker and better bonding effect may be obtained by applying the adhesive intermittently instead of continuously, for example by applying the adhesive in individual steps to produce a row of adjoining dots.

It is therefore an object of the invention to construct the obturating member of a dispensing tank in such manner that neither too much nor too little of the liquid substance is discharged during the opening and closing operations. In accordance with the invention furthermore, the obturating member is designed for high-speed operation permitting the opening and closing movements to proceed, for example, at a frequency of 50 c.p.s., and thus to produce, as it were, a continuous coating Whose appearance is characterised as a row of small adjoining dots.

It has been found that this far-reaching object of the invention can be achieved by providing the closure of the dispensing port in the form of a flexible, thin-walled strip which rests under a determined pressure flat against the inner face of the tank wall in which the dispensing port or orifice is provided. When the obturating strip according to the invention is moved in its plane, the dispensing port may be unblocked or closed by a relatively short stroke, requiring comparatively little closing force since the mass of the thin-walled strip is negligible; there is, furthermore, no risk of displacing a substantial amount of the liquid substance inwardly or outwardly, during the closing or orifice blocking movement.

In one advantageous construction according to the invention, the elongated obturating strip is set at an acute angle against the tank wall, only its end portion of limited length being shaped so as to extend in parallel with the container wall. By disposition at an acute angle to the rigidity or stiffness of the obturating member is increased, while on the other hand the dispensing tank may be provided of relatively small dimensions, since the obturating strip extends substantially obliquely through its interior.

Particular advantages may be afforded by providing the obturating strip in the form of a laminated or leaf spring, inasmuch as laminated or leaf springs satisfy the aforestated condition in respect of thinness of wall, and

. ensure a planar or surface contact under a slight pressure.

so that the rapid oscillating movement of the obturating strip required may be obtained. It will be understood that the same obturating strip may be connected to other driving means, for carrying out any desired movement in respect of the frequency of the closing movement and also in respect of variation of the periods of non-operation and periods of opening.

In accordance with the invention, it has been found to be advantageous for a holding-down device or guide member, for example in the form of a cross-pin, to be provided close to the outlet in such manner that the obturating strip is pressed at each phase of movement against the tank wall in the area of the outlet.

In the case of resilient obturating strips, for example in the case of laminated springs, this contact pressure results from the fact that one end of the strip contacts the inside wall of the tank, and the strip then has to by-pass the holding-down device before it is connected at its other end to the driving means.

In one further advantageous construction according to the invention, the tank wall is hollowed out or is formed internally with an inwardly concave curved portion in a determined area around the dispensing port in such manner that the thickness of the remaining wall (containing the orifice) is very thin, the obturating strip extending into the recess, and the holding-down device being mounted in the side walls within the recess. The thickness of the remaining tank wall need only amount to a few tenths of a millimeter, since it is not required to function as a support. The very thin wall thickness affords the advantage that, as the dispensing port is opened, the liquid substance flows practically instantaneously onto the web to be coated, without capillary forces, frictional forces, or any other negative influence being able to take eifect. It will be understood that the tank wall may also be provided with a continuous opening, which may then be closed on the outside by a thin foil provided with dispensing holes, this affording the advantage that a single dispensing tank may be modified in various ways by means of foils having dispensing holes of differing dimensions.

In accordance with the invention, it is also proposed to join the connecting member by which the movement of thrust is transmitted to the obturating strip, to the driving piston by a cuff-shaped membrane, so that it is only the wall extending parallel to the connecting member which is stressed for extension by the movement of the membrane.

These constructions according to the invention are illustrated by way of example in the accompanying diagrammatic drawings, in which FIGURE 1 is a longitudinal section through a dispensing tank according to the invention;

FIGURE 2 is a section through the tank on the line II-II in FIGURE 1;

FIGURE 3 is a part-longitudinal section of a dispensing tank of a modified construction, and

FIGURE 4 is a longitudinal section through part of a dispensing tank provided with a cuff-shaped membrane.

In the construction illustrated in FIGURE 1, the dispensing tank is denoted generally by the reference numeral 1. The strip of material 2 to be coated, for example a strip of paper, a cutting, or the like, is supported by a non-frictional support 3, preferably made of felt, although numerous other supports may also be used in accordance with the invention. The strip of material 2 is pressed by the dispensing tank 1 snugly against the support 3.

One wall of the tank is hollowed out from the inside to form a recess 5 in the area of the dispensing port 19 (FIGURE 2). The remaining wall 18 is so thin that, when the dispensing port 19 is opened, the adhesive or other liquid substance in the recess 5 can pass practically instantaneously to the strip of material 2. The forward end of the tank wall 4, as considered in the direction of movement of the strip, is provided with a wedge-shaped recess 6 which has been found to have a particularly advantageous effect on the appearance of the coat applied.

The hollow space 7 formed by the remaining tank walls 8 is relatively small. The liquid substance is transferred from a large reservoir into the hollow space 7 through an inlet 17, for example, by means of a flexible tube connection. The tank wall 4 may preferably be connected to the remaining walls 8 so as to be replaceable, for example in order to insert container walls 4 provided with dispensing ports 19 of various constructions to be inserted. The tank wall 4 may, however, also be provided with a continuous opening 5, and instead of the thin tank wall 18, a foil may be secured in position on the outside, in which case the foil is provided with dispensing holes 19. Foils of this kind may be bonded, soldered, or clamped in position, or may be secured to the dispensing tank 1 in any other manner so as to be replaceable.

Extending into the recess 5 is an obturating strip 9, the left-hand end of which rests flat against the tank wall under a determined pressure and thus covers and seals the dispensing port 19. This resilient and flexible obturating strip 9 is passed underneath the holding-down device 11 and flexed, so that the holding-down device 11 may impart the necessary contact pressure between the strip 9 and the dispensing port 19. The other end of the obturating strip 9 is connected, for example, to the armature 10 of a magnet 15, the opening 12 provided for this purpose in the tank being covered by a packing 13 in the form of a membrane, the ends of which are secured by screws 14 to the tank 1, the armature 10 being secured in position in the centre of the membrane 13. The adhesive in the hollow space 7 is thus prevented from entering into any bearing which would thereby be prevented from functioning.

The magnet 15 may, for example, be connected by a strap 16 to the dispensing tank. The manner in which the Whole device 1, 15 is mounted in the machine is determined by the structural data of the machine. The op eration according to the invention is substantially independent of the securing means used.

When the armature 10 of the obturating strip 9 is moved back by the magnet 15 or other driving means, the free end of the obturating strip 9 will uncover the dispensing port 19 (FIGURE 2) and thus enable the adhesive or other liquid substance in the hollow space 7 to be transferred instantaneously to the strip of material 2 which is displaced past the orifice 19 by conventional means represented at 25. As the obturating strip 9 moves back, its end slides, on the inside surface of the tank wall 18, rapidly across the dispensing port 19 thus sealing it ofif against the passage of the liquid. During this closing movement, the continuous flow of adhesive is virtually cut off with the result that operation of the apparatus stops suddenly giving a complete and sharp termination of the coating applied. Smudging and/or delayed starting of a coating which is unavoidable in known devices are completely avoided by the device according to the invention. In practice, it has been found that the obturating strip 9 which, according to the invention, is preferably provided in the form of a laminated spring, may be reciprocated at frequencies as high as 50 c.p.s. provided the strip of material 2 is moved at a corresponding speed. This results in the liquid being applied in the form of dots. In practice it has been shown that this method produces a quicker and firmer bond than a continuous application of the adhesive.

In FIGURE 2 showing a section through the device illustrated in FIGURE 1, it will be noted that the recess 5 may, for example, be provided of rectangular section, the dispensing port 19 being merely a narrow bore. It will be understood that the dispensing port may be provided in the form of a slot or in the form of a plurality of openings. The holding-down device 11 is inserted into the side walls of the recess 5, preferably from the outside, the obturating strip 9 having a slightly smaller width than the recess 5.

FIGURE 3 shows by Way of example a sectional elevation of part of a substantially cylindrical dispensing tank, in which the length of the dispensing port 19 must necessarily exceed that shown in the embodiment illustrated in FIGURE 2. It will be readily understood that the dispensing tank 20 shown in FIGURE 3 operates perfectly as provided by the invention.

FIGURE 4, finally, shows a cuff-shaped membrane 13 of a special construction provided for insertion of the obturating strip 9, 10. In this construction a tubular member 21 is provided which is slightly extended by the reciprocating motion of the obturating strip 9, 10. The purpose of this construction is to prevent to any substantial extent an increase of the pressure of the adhesive in the hollow space 7 and a smudgy application of the adhesive.

It will be appreciated that the constructions in the drawings are by way of example only and that the invention may be carried into practice in other forms.

I claim:

1. Apparatus for the dispensing of a liquid substance, comprising:

a container for said substance having a wall provided with an orifice for the discharge of said substance;

an elongated resilient closure strip having one end slidably urged against the inner surface of said wall in the vicinity of said orifice and extending away from the inner surface of said wall into the interior of said container along the major portion of the length of said strip;

drive means coupled to the other end of said strip With in said container at a location removed from the inner surfaces of said container for selectively sliding said strip along said wall to block and unblock said orifice; and

a guide member mounted within the container intermediate said orifice and said location and engaging only a limited part of the length of said strip for urging said one end against said wall and directing said one 5 end toward said orifice.

2. An apparatus as defined in claim 1 wherein: said strip is a thin-walled leaf spring; said wall is formed with an inwardly curvilinearly concave recess having a thin-wall portion surrounding said orifice and slidably engaged in surface contact by said one end; and said guide member is mounted within said recess in said wall. 3. An apparatus as defined in claim 2, further comprising a pad disposed outside said container opposite said wall and spaced from said orifice for supporting a web of material to be passed therebetween.

4. An apparatus as defiined in claim 2 wherein said drive means is an electromagnet disposed externally of said container and having an actuating rod extending into the latter to said location, said apparatus further comprising an annular flexible diaphragm connecting said rod with said container.

References Cited 25 UNITED STATES PATENTS 341,758 5/ 1886 Livingston 118415 X 1,901,413 3/1933 Roselle 222 560 X 2,200,923 5/1940 Hoggatt 222 560 X 2,312,584 3/1943 Peterson 222561 X 3,034,761 5/ 1962 Janquart.

CHARLES A. WILLMUT H, Primary Examiner. J. P. MCINTOSH, Assistant Examiner. 

